AUTHOR'S COMMENTS AND ACKNOWLEDGMENTS 



THE excellent reception accorded to the first edi- 

 tion of this book was highly gratifying and 

 stimulating. This necessitated the preparation of a 

 second edition, work on which started in early 1946. 

 The contents of the book have been enlarged by 

 including many new subjects of biochemical, enzy- 

 mological and immunological interest, including a 

 chapter on the physiology and biochemistry of ana- 

 phylaxis. 



The author takes this occasion to express his in- 

 debtedness to many friends, readers and reviewers 

 here and abroad whose comments have been a con- 

 stant source of stimulation. 



- During the preparation of the manuscript for this 

 edition I have enjoyed the privilege of carrying on 

 research under grants to the University of Pennsyl- 

 vania from the Josiah Macy, Jr., Foundation and 

 from the United States Public Health Service. 



I wish to express my appreciation to Dr. Otto 

 Rosenthal of the Department of Research Surgery, 

 and to Dr. Seymour S. Kety of the Department of 

 Pharmacology of the Graduate School of Medicine, 

 and to Dr. John R. Preer of the Department of 

 Zoology, for valuable aid received in the preparation 

 of certain sections. Special thanks are due to Dr. 

 John Flick and Professor Stuart Mudd for their con- 

 stant stimulating interest and their painstaking read- 

 ing of the entire manuscript. Their most valuable 

 suggestions are incorporated into the text. 



M. G. Sevag 





